Next Issue
Volume 10, August-2
Previous Issue
Volume 10, July-2

Electronics, Volume 10, Issue 15 (August-1 2021) – 123 articles

Cover Story (view full-size image): The expansion of electric vehicles in urban areas has paved the way toward the era of autonomous vehicles. This field of research opens immediate applications in the tourism areas, airports, or business centers. This project shows the problems derived from autonomous driving such as vehicle localization, low coverage of 4G/5G and GPS, detection of the road and navigable zones, detection of static and dynamic obstacles, longitudinal and lateral control, and cybersecurity aspects. The approaches proposed in this article are sufficient to solve problems related to autonomous vehicle application in special locations on unstructured roads. View this paper.
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Order results
Result details
Select all
Export citation of selected articles as:
Article
A Low Spur and Low Jitter Quadrature LO-Generator Using CML Inductive Peaking Technique for WLAN Transceiver
Electronics 2021, 10(15), 1869; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151869 - 03 Aug 2021
Viewed by 405
Abstract
The demand for a local oscillator (LO) signal of high quality and integrity in local area network (WLAN) communication is growing with the increasing date rate. The LO signals for high data rate WLAN applications are desired to not only have proper shape [...] Read more.
The demand for a local oscillator (LO) signal of high quality and integrity in local area network (WLAN) communication is growing with the increasing date rate. The LO signals for high data rate WLAN applications are desired to not only have proper shape waveforms and adequate voltage amplitude but also to achieve relatively stable and clean outputs with low phase noise and low spur. Fractional-N frequency planning is critical for a quadrature LO-generator, which is achieved by a single-sideband (SSB) mixer and multiple dividers since it can avoid the frequency pulling and alleviate the self-mixing and DC offset issues, while spur levels are easily increased due to harmonic mixing, imbalance, and leakage of the SSB mixer. This article proposes a simple and innovative quadrature LO-generator, which adopts a current-mode-logic (CML) inductive peaking (IP) circuit to improve phase noise and suppress spurious tones. Four types of LO delivery methods using IP circuits are proposed and compared. Among four methods, the CML-IP circuit presents the optimum performance for driving long wires of multi-mm length. Instead of previous digital spur cancellation, the CML-IP circuit achieves higher spur suppression, lower jitter, and a greater figure of merit (FoM). The quadrature LO-generator can be configured to either VCO mode or bypass mode supporting external VCO input. Implemented in 55 nm CMOS technology, the proposed quadrature LO-generator achieves −52.6 dBc spur suppression, −142 dBc/Hz phase noise at 1 MHz offset at the 4.8 GHz frequency, and −271 FoM. Furthermore, the quadrature LO-generator occupies an active area of 0.178 mm2 and consumes 23.86 mW. Full article
(This article belongs to the Special Issue RF/Mm-Wave Circuits Design and Applications)
Show Figures

Figure 1

Article
A Secure Link-Layer Connectivity Platform for Multi-Site NFV Services
Electronics 2021, 10(15), 1868; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151868 - 03 Aug 2021
Viewed by 403
Abstract
Network Functions Virtualization (NFV) is a key technology for network automation and has been instrumental to materialize the disruptive view of 5G and beyond mobile networks. In particular, 5G embraces NFV to support the automated and agile provision of telecommunication and vertical services [...] Read more.
Network Functions Virtualization (NFV) is a key technology for network automation and has been instrumental to materialize the disruptive view of 5G and beyond mobile networks. In particular, 5G embraces NFV to support the automated and agile provision of telecommunication and vertical services as a composition of versatile virtualized components, referred to as Virtual Network Functions (VNFs). It provides a high degree of flexibility in placing these components on distributed NFV infrastructures (e.g., at the network edge, close to end users). Still, this flexibility creates new challenges in terms of VNF connectivity. To address these challenges, we introduce a novel secure link-layer connectivity platform, L2S. Our solution can automatically be deployed and configured as a regular multi-site NFV service, providing the abstraction of a layer-2 switch that offers link-layer connectivity to VNFs deployed on remote NFV sites. Inter-site communications are effectively protected using existing security solutions and protocols, such as IP security (IPsec). We have developed a functional prototype of L2S using open-source software technologies. Our evaluation results indicate that this prototype can perform IP tunneling and cryptographic operations at Gb/s data rates. Finally, we have validated L2S using a multi-site NFV ecosystem at the Telefonica Open Network Innovation Centre (5TONIC), using our solution to support a multicast-based IP television service. Full article
(This article belongs to the Special Issue Novel Cloud-Based Service/Application Platforms and Ecosystems)
Show Figures

Figure 1

Article
IC-Based Neuro-Stimulation Environment for Arbitrary Waveform Generation
Electronics 2021, 10(15), 1867; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151867 - 03 Aug 2021
Viewed by 392
Abstract
Electrical stimulation of the nervous system is commonly based on biphasic stimulation waveforms, which limits its relevance for some applications, such as selective stimulation. We propose in this paper a stimulator capable of delivering arbitrary waveforms to electrodes, and suitable for non-conventional stimulation [...] Read more.
Electrical stimulation of the nervous system is commonly based on biphasic stimulation waveforms, which limits its relevance for some applications, such as selective stimulation. We propose in this paper a stimulator capable of delivering arbitrary waveforms to electrodes, and suitable for non-conventional stimulation strategies. Such a system enables in vivo stimulation protocols with optimized efficacy or energy efficiency. The designed system comprises a High Voltage CMOS ASIC generating a configurable stimulating current, driven by a digital circuitry implemented on a FPGA. After fabrication, the ASIC and system were characterized and tested; they successfully generated programmable waveforms with a frequential content up to 1.2 MHz and a voltage compliance between [−17.9; +18.3] V. The system is not optimum when compared to single application stimulators, but no embedded stimulator in the literature offers an equivalent bandwidth which allows the wide range of stimulation paradigms, including high-frequency blocking stimulation. We consider that this stimulator will help test unconventional stimulation waveforms and can be used to generate proof-of-concept data before designing implantable and application-dedicated implantable stimulators. Full article
(This article belongs to the Section Bioelectronics)
Show Figures

Figure 1

Article
Application of Particle Swarm Optimization in the Design of an ICT High-Voltage Power Supply with Dummy Primary Winding
Electronics 2021, 10(15), 1866; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151866 - 03 Aug 2021
Viewed by 283
Abstract
The distribution of disk output voltage is a key factor for the design of an insulated core transformer (ICT) high-voltage power supply. The development of an ICT involves the design and optimization of many parameters, which greatly affect the uniformity of disk output [...] Read more.
The distribution of disk output voltage is a key factor for the design of an insulated core transformer (ICT) high-voltage power supply. The development of an ICT involves the design and optimization of many parameters, which greatly affect the uniformity of disk output voltage. A new ICT structure with dummy primary windings can compensate for the disk output voltage, which aims to improve uniformity. In this work, an optimization method based on a particle swarm optimization (PSO) algorithm was used to optimize the design parameters of an ICT with dummy primary windings. It achieved an optimal uniformity of disk output voltage and load regulation. The design parameters, including the number of secondary winding turns and the compensation capacitance, were optimized based on the finite-element method (FEM) and Simulink circuit simulation. The results show that the maximum non-uniformity of the disk output voltage is reduced from 11.1% to 4.4% from no-load to a full load for a 200 kV/20 mA HUST-ICT prototype. Moreover, the load regulation is greatly reduced from 14.3% to 9.6%. The method improves the stability and reliability of the ICT high voltage power supply and greatly reduces the design time. Full article
(This article belongs to the Special Issue Robust Design Optimization of Electrical Machines and Devices)
Show Figures

Figure 1

Article
Sub-/Super-SCI Influencing Factors Analysis of VSC-HVDC and PMSG-Wind Farm System by Impedance Bode Criterion
Electronics 2021, 10(15), 1865; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151865 - 03 Aug 2021
Viewed by 296
Abstract
A sub-/super-synchronous interaction (sub-/super-SCI) can occur between a voltage source converter-based high-voltage direct current (VSC-HVDC) and the permanent magnet synchronous generator (PMSG)-based wind farms with long AC transmission lines. However, the influencing factors have not been properly analyzed. In this paper, these are [...] Read more.
A sub-/super-synchronous interaction (sub-/super-SCI) can occur between a voltage source converter-based high-voltage direct current (VSC-HVDC) and the permanent magnet synchronous generator (PMSG)-based wind farms with long AC transmission lines. However, the influencing factors have not been properly analyzed. In this paper, these are deconstructed and mathematically analyzed from detailed small-signal impedance equations in the dq-frame and the corresponding Bode stability criterion. Distinguishing conclusions from existing papers are obtained by studying the controllers’ bandwidths instead of their coefficients. The impacts of AC line impedance on system stability are also investigated. From the analysis of their compositions in impedance structure, the VSC-HVDC bandwidths and the wind farm phase-locked loop (PLL) bandwidth and power ratio, and the AC line impedance have various influences on the system stability. Meanwhile, the wind farm outer DC voltage and inner current control bandwidths have little impact on system stability. The results of these studies show that the magnitude in the axes q-axes impedance interaction is the essential factor for system instability. Our studies also show system stability is more sensitive to the HVDC bandwidths than the wind converter PLL bandwidth. The simulation results verify our theory conclusions. Full article
(This article belongs to the Section Power Electronics)
Show Figures

Figure 1

Article
UAV Object Tracking Application Based on Patch Color Group Feature on Embedded System
Electronics 2021, 10(15), 1864; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151864 - 03 Aug 2021
Viewed by 331
Abstract
The discriminative object tracking system for unmanned aerial vehicles (UAVs) is widely used in numerous applications. While an ample amount of research has been carried out in this domain, implementing a low computational cost algorithm on a UAV onboard embedded system is still [...] Read more.
The discriminative object tracking system for unmanned aerial vehicles (UAVs) is widely used in numerous applications. While an ample amount of research has been carried out in this domain, implementing a low computational cost algorithm on a UAV onboard embedded system is still challenging. To address this issue, we propose a low computational complexity discriminative object tracking system for UAVs approach using the patch color group feature (PCGF) framework in this work. The tracking object is separated into several non-overlapping local image patches then the features are extracted into the PCGFs, which consist of the Gaussian mixture model (GMM). The object location is calculated by the similar PCGFs comparison from the previous frame and current frame. The background PCGFs of the object are removed by four directions feature scanning and dynamic threshold comparison, which improve the performance accuracy. In the terms of speed execution, the proposed algorithm accomplished 32.5 frames per second (FPS) on the x64 CPU platform without a GPU accelerator and 17 FPS in Raspberry Pi 4. Therefore, this work could be considered as a good solution for achieving a low computational complexity PCGF algorithm on a UAV onboard embedded system to improve flight times. Full article
(This article belongs to the Special Issue UAV-Femtocell Systems and Applications)
Show Figures

Figure 1

Article
Alternative Measures of Dependence for Cyclic Behaviour Identification in the Signal with Impulsive Noise—Application to the Local Damage Detection
Electronics 2021, 10(15), 1863; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151863 - 03 Aug 2021
Viewed by 341
Abstract
The local damage detection procedures in rotating machinery are based on the analysis of the impulsiveness and/or the periodicity of disturbances corresponding to the failure. Recent findings related to non-Gaussian vibration signals showed some drawbacks of the classical methods. If the signal is [...] Read more.
The local damage detection procedures in rotating machinery are based on the analysis of the impulsiveness and/or the periodicity of disturbances corresponding to the failure. Recent findings related to non-Gaussian vibration signals showed some drawbacks of the classical methods. If the signal is noisy and it is strongly non-Gaussian (heavy-tailed), searching for impulsive behvaior is pointless as both informative and non-informative components are transients. The classical dependence measure (autocorrelation) is not suitable for non-Gaussian signals. Thus, there is a need for new methods for hidden periodicity detection. In this paper, an attempt will be made to use alternative measures of dependence used in time series analysis that are less known in the condition monitoring (CM) community. They are proposed as alternatives for the classical autocovariance function used in the cyclostationary analysis. The methodology of the auto-similarity map calculation is presented as well as a procedure for a “quality” or “informativeness” assessment of the map is proposed. In the most complex case, the most resistant to heavy-tailed noise turned out the proposed techniques based on Kendall, Spearman and Quadrant autocorrelations. Whereas in the case of the local fault disturbed by the Gaussian noise, the most efficient proved to be a commonly-known approach based on Pearson autocorrelation. The ideas proposed in the paper are supported by simulation signals and real vibrations from heavy-duty machines. Full article
(This article belongs to the Section Circuit and Signal Processing)
Show Figures

Figure 1

Article
An Intelligent Hybrid–Integrated System Using Speech Recognition and a 3D Display for Early Childhood Education
Electronics 2021, 10(15), 1862; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151862 - 03 Aug 2021
Viewed by 278
Abstract
In the past few years, people’s attitudes toward early childhood education (PAUD) have undergone a complete transformation. Personalized and intelligent communication methods are highly praised, which also promotes the further focus on timely and effective human–computer interaction. Since traditional English learning that relies [...] Read more.
In the past few years, people’s attitudes toward early childhood education (PAUD) have undergone a complete transformation. Personalized and intelligent communication methods are highly praised, which also promotes the further focus on timely and effective human–computer interaction. Since traditional English learning that relies on parents consumes more time and energy and is prone to errors and omissions, this paper proposes a system based on a convolution neural network (CNN) and automatic speech recognition (ASR) to achieve an integrated process of object recognition, intelligent speech interaction, and synchronization of learning records in children’s education. Compared with platforms described in the literature, not only does it shoot objects in the real-life environment to obtain English words, their pronunciation, and example sentences corresponding to them, but also it combines the technique of a three-dimensional display to help children learn abstract words. At the same time, the cloud database summarizes and tracks the learning progress by a horizontal comparison, which makes it convenient for parents to figure out the situation. The performance evaluation of image and speech recognition demonstrates that the overall accuracy remains above 96%. Through comprehensive experiments in different scenarios, we prove that the platform is suitable for children as an auxiliary method and cultivates their interest in learning English. Full article
Show Figures

Figure 1

Article
A Short Survey on Machine Learning Explainability: An Application to Periocular Recognition
Electronics 2021, 10(15), 1861; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151861 - 03 Aug 2021
Viewed by 383
Abstract
Interpretability has made significant strides in recent years, enabling the formerly black-box models to reach new levels of transparency. These kinds of models can be particularly useful to broaden the applicability of machine learning-based systems to domains where—apart from the predictions—appropriate justifications are [...] Read more.
Interpretability has made significant strides in recent years, enabling the formerly black-box models to reach new levels of transparency. These kinds of models can be particularly useful to broaden the applicability of machine learning-based systems to domains where—apart from the predictions—appropriate justifications are also required (e.g., forensics and medical image analysis). In this context, techniques that focus on visual explanations are of particular interest here, due to their ability to directly portray the reasons that support a given prediction. Therefore, in this document, we focus on presenting the core principles of interpretability and describing the main methods that deliver visual cues (including one that we designed for periocular recognition in particular). Based on these intuitions, the experiments performed show explanations that attempt to highlight the most important periocular components towards a non-match decision. Then, some particularly challenging scenarios are presented to naturally sustain our conclusions and thoughts regarding future directions. Full article
(This article belongs to the Special Issue 10th Anniversary of Electronics: Hot Topics in Bioelectronics)
Show Figures

Figure 1

Article
Terahertz High-Q Absorber Based on Holes Array Perforated into a Metallic Slab
Electronics 2021, 10(15), 1860; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151860 - 02 Aug 2021
Viewed by 381
Abstract
In this paper, we theoretically analyze and design a dual-narrowband terahertz (THz) absorber based on a hole array drilled into a metallic slab. A very high-quality factor (Q) is achieved at both of the resonance frequencies. A circuit model-based approach is [...] Read more.
In this paper, we theoretically analyze and design a dual-narrowband terahertz (THz) absorber based on a hole array drilled into a metallic slab. A very high-quality factor (Q) is achieved at both of the resonance frequencies. A circuit model-based approach is developed for the analysis and design of the proposed absorber. The absorption peaks occur at 2.46 and 3.75 THz frequencies with 98% and 96% absorptions at normal incidence, respectively. The achieved quality factors are 149 and 144, at 50% absorbance for the two absorption bands, respectively. Full article
(This article belongs to the Special Issue Microwave Devices Design and Application)
Show Figures

Figure 1

Article
Battery Management System Algorithm for Energy Storage Systems Considering Battery Efficiency
Electronics 2021, 10(15), 1859; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151859 - 02 Aug 2021
Cited by 1 | Viewed by 424
Abstract
Aging increases the internal resistance of a battery and reduces its capacity; therefore, energy storage systems (ESSs) require a battery management system (BMS) algorithm that can manage the state of the battery. This paper proposes a battery efficiency calculation formula to manage the [...] Read more.
Aging increases the internal resistance of a battery and reduces its capacity; therefore, energy storage systems (ESSs) require a battery management system (BMS) algorithm that can manage the state of the battery. This paper proposes a battery efficiency calculation formula to manage the battery state. The proposed battery efficiency calculation formula uses the charging time, charging current, and battery capacity. An algorithm that can accurately determine the battery state is proposed by applying the proposed state of charge (SoC) and state of health (SoH) calculations. To reduce the initial error of the Coulomb counting method (CCM), the SoC can be calculated accurately by applying the battery efficiency to the open circuit voltage (OCV). During the charging and discharging process, the internal resistance of a battery increase and the constant current (CC) charging time decrease. The SoH can be predicted from the CC charging time of the battery and the battery efficiency, as proposed in this paper. Furthermore, a safe system is implemented during charging and discharging by applying a fault diagnosis algorithm to reduce the battery efficiency. The validity of the proposed BMS algorithm is demonstrated by applying it in a 3-kW ESS. Full article
(This article belongs to the Special Issue Energy Harvesting and Energy Storage Systems)
Show Figures

Figure 1

Article
Quadrature Demodulator-Assisted Estimation of Load Voltage and Resistance Based on Primary-Side Information of a Wireless Power Transfer Link
Electronics 2021, 10(15), 1858; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151858 - 02 Aug 2021
Cited by 1 | Viewed by 322
Abstract
This paper proposes an algorithm for the extraction of primary-side first harmonic voltage and current components for inductive wireless power transfer (WPT) links by employing quadrature demodulation. Such information allows for the accurate estimation of corresponding receiver-side components and hence permits the monitoring [...] Read more.
This paper proposes an algorithm for the extraction of primary-side first harmonic voltage and current components for inductive wireless power transfer (WPT) links by employing quadrature demodulation. Such information allows for the accurate estimation of corresponding receiver-side components and hence permits the monitoring of the output voltage and resistance necessary for protection and/or control without using either sensors or feedback communication. It is shown that precision estimation is held as long as the parameter values of the system are known and the phasor-domain equivalent circuit is valid (i.e., in continuous conduction mode). On the other hand, upon light load operation (i.e., in discontinuous conduction mode), the proposed technique may still be employed if suitable nonlinear correction is employed. The methodology is applied to a 400 V, 1 kW inductive WPT link operating at a load-independent-voltage-output frequency and is well-verified both by simulations and experiments. Full article
(This article belongs to the Special Issue Advances in Wireless Power Transfer and Applications)
Show Figures

Figure 1

Article
Evolutionary Convolutional Neural Network Optimization with Cross-Tasks Transfer Strategy
Electronics 2021, 10(15), 1857; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151857 - 02 Aug 2021
Viewed by 338
Abstract
Convolutional neural networks (CNNs) have shown great success in a variety of real-world applications and the outstanding performance of the state-of-the-art CNNs is primarily driven by the elaborate architecture. Evolutionary convolutional neural network (ECNN) is a promising approach to design the optimal CNN [...] Read more.
Convolutional neural networks (CNNs) have shown great success in a variety of real-world applications and the outstanding performance of the state-of-the-art CNNs is primarily driven by the elaborate architecture. Evolutionary convolutional neural network (ECNN) is a promising approach to design the optimal CNN architecture automatically. Nevertheless, most of the existing ECNN methods only focus on improving the performance of the discovered CNN architectures without considering the relevance between different classification tasks. Transfer learning is a human-like learning approach and has been introduced to solve complex problems in the domain of evolutionary algorithms (EAs). In this paper, an effective ECNN optimization method with cross-tasks transfer strategy (CTS) is proposed to facilitate the evolution process. The proposed method is then evaluated on benchmark image classification datasets as a case study. The experimental results show that the proposed method can not only speed up the evolutionary process significantly but also achieve competitive classification accuracy. To be specific, our proposed method can reach the same accuracy at least 40 iterations early and an improvement of accuracy for 0.88% and 3.12% on MNIST-FASHION and CIFAR10 datasets compared with ECNN, respectively. Full article
(This article belongs to the Special Issue Applications of Computational Intelligence)
Show Figures

Figure 1

Article
A Study on the Variable Inductor Design by Switching the Main Paths and the Coupling Coils
Electronics 2021, 10(15), 1856; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151856 - 02 Aug 2021
Viewed by 319
Abstract
In a radio frequency (RF) system, it is possible to use variable inductors for providing tunable or selective frequency range. Variable inductors can be implemented by the microelectromechanical system (MEMS) process or by using transistors as switches to change the routing of coils [...] Read more.
In a radio frequency (RF) system, it is possible to use variable inductors for providing tunable or selective frequency range. Variable inductors can be implemented by the microelectromechanical system (MEMS) process or by using transistors as switches to change the routing of coils or coupling quantities. In this paper, we investigated the design method of a variable inductor by using MOS transistors to switch the main coil paths and the secondary coupled coils. We observed the effects of different metal layers, turn numbers, and layout arrangements for secondary-coupled coils and compared their characteristics on the inductances and quality factors. We implemented two chips in the 0.18 μm CMOS process technology for each kind of arrangement for verification. One inductor can achieve inductance values from about 300 pH to 550 pH, and the other is between 300 pH and 575 pH, corresponding to 59.3% and 62.5%, respectively, inductance variation range at 4 GHz frequency. Additionally, their fine step sizes of the switched inductances are from 0.5% to 6% for one design, and 1% to 12.5% for the other. We found that both designs achieved a large inductance tuning range and moderate inductance step sizes with a slight difference behavior on the inductance variation versus frequency. Full article
(This article belongs to the Section Microelectronics)
Show Figures

Figure 1

Article
A Non-Interactive Attribute-Based Access Control Scheme by Blockchain for IoT
Electronics 2021, 10(15), 1855; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151855 - 01 Aug 2021
Viewed by 446
Abstract
As an important method of protecting data confidentiality in the Internet of Things (IoT), access control has been widely concerned. Because attribute-based access control mechanisms are dynamic, it is not only suitable to solve the dynamic access problem in IoT, but also to [...] Read more.
As an important method of protecting data confidentiality in the Internet of Things (IoT), access control has been widely concerned. Because attribute-based access control mechanisms are dynamic, it is not only suitable to solve the dynamic access problem in IoT, but also to deal with the dynamic caused by node movement and access data change. The traditional centralized attribute-based access control mechanism has some problems: due to the large number of devices in IoT, the central trusted entity may become the bottleneck of the whole system. Moreover, when a central trusted entity is under distributed denial-of-service (DDoS) attack, the entire system may crash. Blockchain is a good way to solve the above problems. Therefore, we developed a non-interactive, attribute-based access control scheme that applies blockchain technology in IoT scenarios by using PSI technology. In addition, the attributes of data user and data holder are hidden, which protects the privacy of both parties’ attributes and access policy. Furthermore, the experimental results indicate that our scheme has high efficiency. Full article
Show Figures

Figure 1

Article
A Novel Approach for Network Intrusion Detection Using Multistage Deep Learning Image Recognition
Electronics 2021, 10(15), 1854; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151854 - 01 Aug 2021
Viewed by 450
Abstract
The current rise in hacking and computer network attacks throughout the world has heightened the demand for improved intrusion detection and prevention solutions. The intrusion detection system (IDS) is critical in identifying abnormalities and assaults on the network, which have grown in size [...] Read more.
The current rise in hacking and computer network attacks throughout the world has heightened the demand for improved intrusion detection and prevention solutions. The intrusion detection system (IDS) is critical in identifying abnormalities and assaults on the network, which have grown in size and pervasiveness. The paper proposes a novel approach for network intrusion detection using multistage deep learning image recognition. The network features are transformed into four-channel (Red, Green, Blue, and Alpha) images. The images then are used for classification to train and test the pre-trained deep learning model ResNet50. The proposed approach is evaluated using two publicly available benchmark datasets, UNSW-NB15 and BOUN Ddos. On the UNSW-NB15 dataset, the proposed approach achieves 99.8% accuracy in the detection of the generic attack. On the BOUN DDos dataset, the suggested approach achieves 99.7% accuracy in the detection of the DDos attack and 99.7% accuracy in the detection of the normal traffic. Full article
(This article belongs to the Special Issue Design of Intelligent Intrusion Detection Systems)
Show Figures

Figure 1

Article
Determination of Traffic Characteristics of Elastic Optical Networks Nodes with Reservation Mechanisms
Electronics 2021, 10(15), 1853; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151853 - 01 Aug 2021
Viewed by 365
Abstract
With the ever-increasing demand for bandwidth, appropriate mechanisms that would provide reliable and optimum service level to designated or specified traffic classes during heavy traffic loads in networks are becoming particularly sought after. One of these mechanisms is the resource reservation mechanism, in [...] Read more.
With the ever-increasing demand for bandwidth, appropriate mechanisms that would provide reliable and optimum service level to designated or specified traffic classes during heavy traffic loads in networks are becoming particularly sought after. One of these mechanisms is the resource reservation mechanism, in which parts of the resources are available only to selected (pre-defined) services. While considering modern elastic optical networks (EONs) where advanced data transmission techniques are used, an attempt was made to develop a simulation program that would make it possible to determine the traffic characteristics of the nodes in EONs. This article discusses a simulation program that has the advantage of providing the possibility to determine the loss probability for individual service classes in the nodes of an EON where the resource reservation mechanism has been introduced. The initial assumption in the article is that a Clos optical switching network is used to construct the EON nodes. The results obtained with the simulator developed by the authors will allow the influence of the introduced reservation mechanism on the loss probability of calls of individual traffic classes that are offered to the system under consideration to be determined. Full article
(This article belongs to the Special Issue 10th Anniversary of Electronics: Advances in Networks)
Show Figures

Figure 1

Article
Frequency Estimation from Compressed Measurements of a Sinusoid in Moving-Average Colored Noise
Electronics 2021, 10(15), 1852; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151852 - 31 Jul 2021
Viewed by 331
Abstract
Frequency estimation of a single sinusoid in colored noise has received a considerable amount of attention in the research community. Taking into account the recent emergence and advances in compressive covariance sensing (CCS), the aim of this work is to combine the two [...] Read more.
Frequency estimation of a single sinusoid in colored noise has received a considerable amount of attention in the research community. Taking into account the recent emergence and advances in compressive covariance sensing (CCS), the aim of this work is to combine the two disciplines by studying the effects of compressed measurements of a single sinusoid in moving-average colored noise on its frequency estimation accuracy. CCS techniques can recover the second-order statistics of the original uncompressed signal from the compressed measurements, thereby enabling correlation-based frequency estimation of single tones in colored noise using higher order lags. Acceptable accuracy is achieved for moderate compression ratios and for a sufficiently large number of available compressed signal samples. It is expected that the proposed method would be advantageous in applications involving resource-limited systems such as wireless sensor networks. Full article
(This article belongs to the Special Issue Novel Technologies on Image and Signal Processing)
Show Figures

Figure 1

Article
Design of Efficient Human Head Statistics System in the Large-Angle Overlooking Scene
Electronics 2021, 10(15), 1851; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151851 - 31 Jul 2021
Viewed by 376
Abstract
Human head statistics is widely used in the construction of smart cities and has great market value. In order to solve the problem of missing pedestrian features and poor statistics results in a large-angle overlooking scene, in this paper we propose a human [...] Read more.
Human head statistics is widely used in the construction of smart cities and has great market value. In order to solve the problem of missing pedestrian features and poor statistics results in a large-angle overlooking scene, in this paper we propose a human head statistics system that consists of head detection, head tracking and head counting, where the proposed You-Only-Look-Once-Head (YOLOv5-H) network, improved from YOLOv5, is taken as the head detection benchmark, the DeepSORT algorithm with the Fusion-Hash algorithm for feature extraction (DeepSORT-FH) is proposed to track heads, and heads are counted by the proposed cross-boundary counting algorithm based on scene segmentation. Specifically, Complete-Intersection-over-Union (CIoU) is taken as the loss function of YOLOv5-H to make the predicted boxes more in line with the real boxes. The results demonstrate that the recall rate and [email protected] of the proposed YOLOv5-H can reach up to 94.3% and 93.1%, respectively, on the SCUT_HEAD dataset. The statistics system has an extremely low error rate of 3.5% on the TownCentreXVID dataset while maintaining a frame rate of 18FPS, which can meet the needs of human head statistics in monitoring scenarios and has a good application prospect. Full article
(This article belongs to the Section Computer Science & Engineering)
Show Figures

Figure 1

Article
Analysis of Obstacle Avoidance Strategy for Dual-Arm Robot Based on Speed Field with Improved Artificial Potential Field Algorithm
Electronics 2021, 10(15), 1850; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151850 - 31 Jul 2021
Viewed by 339
Abstract
In recent years, dual-arm robots have been favored in various industries due to their excellent coordinated operability. One of the focused areas of study on dual-arm robots is obstacle avoidance, namely path planning. Among the existing path planning methods, the artificial potential field [...] Read more.
In recent years, dual-arm robots have been favored in various industries due to their excellent coordinated operability. One of the focused areas of study on dual-arm robots is obstacle avoidance, namely path planning. Among the existing path planning methods, the artificial potential field (APF) algorithm is widely applied in obstacle avoidance for its simplicity, practicability, and good real-time performance over other planning methods. However, APF is firstly proposed to solve the obstacle avoidance problem of mobile robot in plane, and thus has some limitations such as being prone to fall into local minimum, not being applicable when dynamic obstacles are encountered. Therefore, an obstacle avoidance strategy for a dual-arm robot based on speed field with improved artificial potential field algorithm is proposed. In our method, the APF algorithm is used to establish the attraction and repulsion functions of the robotic manipulator, and then the concepts of attraction and repulsion speed are introduced. The attraction and repulsion functions are converted into the attraction and repulsion speed functions, which mapped to the joint space. By using the Jacobian matrix and its inverse to establish the differential velocity function of joint motion, as well as comparing it with the set collision distance threshold between two robotic manipulators of robot, the collision avoidance can be solved. Meanwhile, after introducing a new repulsion function and adding virtual constraint points to eliminate existing limitations, APF is also improved. The correctness and effectiveness of the proposed method in the self-collision avoidance problem of a dual-arm robot are validated in MATLAB and Adams simulation environment. Full article
(This article belongs to the Section Systems & Control Engineering)
Show Figures

Figure 1

Article
Analysis and Implementation of Threat Agents Profiles in Semi-Automated Manner for a Network Traffic in Real-Time Information Environment
Electronics 2021, 10(15), 1849; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151849 - 31 Jul 2021
Viewed by 498
Abstract
Threat assessment is the continuous process of monitoring the threats identified in the network of the real-time informational environment of an organisation and the business of the companies. The sagacity and security assurance for the system of an organisation and company’s business seem [...] Read more.
Threat assessment is the continuous process of monitoring the threats identified in the network of the real-time informational environment of an organisation and the business of the companies. The sagacity and security assurance for the system of an organisation and company’s business seem to need that information security exercise to unambiguously and effectively handle the threat agent’s attacks. How is this unambiguous and effective way in the present-day state of information security practice working? Given the prevalence of threats in the modern information environment, it is essential to guarantee the security of national information infrastructure. However, the existing models and methodology are not addressing the attributes of threats like motivation, opportunity, and capability (C, M, O), and the critical threat intelligence (CTI) feed to the threat agents during the penetration process is ineffective, due to which security assurance arises for an organisation and the business of companies. This paper proposes a semi-automatic information security model, which can deal with situational awareness data, strategies prevailing information security activities, and protocols monitoring specific types of the network next to the real-time information environment. This paper looks over analyses and implements the threat assessment of network traffic in one particular real-time informational environment. To achieve this, we determined various unique attributes of threat agents from the Packet Capture Application Programming Interface (PCAP files/DataStream) collected from the network between the years 2012 and 2019. We used hypothetical and real-world examples of a threat agent to evaluate the three different factors of threat agents, i.e., Motivation, Opportunity, and Capability (M, O, C). Based on this, we also designed and determined the threat profiles, critical threat intelligence (CTI), and complexity of threat agents that are not addressed or covered in the existing threat agent taxonomies models and methodologies. Full article
(This article belongs to the Special Issue Cybersecurity and Data Science)
Show Figures

Figure 1

Article
A Hybrid Control Scheme with Fast Transient and Low Harmonic for Boost PFC Converter
Electronics 2021, 10(15), 1848; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151848 - 31 Jul 2021
Viewed by 289
Abstract
In this study, a new control strategy was proposed to improve transient response and the input current harmonic distortion of power factor correction (PFC) regulators operating in an average current mode. The proposed technique required only two additional gain selectors and a peak [...] Read more.
In this study, a new control strategy was proposed to improve transient response and the input current harmonic distortion of power factor correction (PFC) regulators operating in an average current mode. The proposed technique required only two additional gain selectors and a peak detector circuit on the feedforward voltage loop and output voltage feedback loops. It provided a direct reading for the average voltage value of feedback control loops and the peak voltage of feedforward control loops, producing PFC boost regulators with fast dynamic responses and low-input current harmonic distortion. The use of digital potentiometers for directly changing the gain of control loops did not require any divider or squarer to reduce the complexity of control circuits. The operating principles and control strategies of 300 W boost PFC with the new control strategy are presented with detailed analysis and discussion. The experimental results were satisfactory. Full article
(This article belongs to the Special Issue Automotive Electronics)
Show Figures

Figure 1

Article
Joint Successful Transmission Probability, Delay, and Energy Efficiency Caching Optimization in Fog Radio Access Network
Electronics 2021, 10(15), 1847; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151847 - 31 Jul 2021
Viewed by 324
Abstract
The fog radio access network (F-RAN) is considered an efficient architecture for caching technology as it can support both edge and centralized caching due to the backhauling of the fog access points (F-APs). Successful transmission probability (STP), delay, and energy efficiency (EE) are [...] Read more.
The fog radio access network (F-RAN) is considered an efficient architecture for caching technology as it can support both edge and centralized caching due to the backhauling of the fog access points (F-APs). Successful transmission probability (STP), delay, and energy efficiency (EE) are key performance metrics for F-RAN. Therefore, this paper proposes a proactive cache placement scheme that jointly optimizes STP, delay, and EE in wireless backhauled cache-enabled F-RAN. First, expressions of the association probability, STP, average delay, and EE are derived using stochastic geometry tools. Then, the optimization problem is formulated to obtain the optimal cache placement that maximizes the weighted sum of STP, EE, and negative delay. To solve the optimization problem, this paper proposes the normalized cuckoo search algorithm (NCSA), which is a novel modified version of the cuckoo search algorithm (CSA). In NCSA, after generating the solutions randomly via Lévy flight and random walk, a simple bound is applied, and then the solutions are normalized to assure their feasibility. The numerical results show that the proposed joint cache placement scheme can effectively achieve significant performance improvement by up to 15% higher STP, 45% lower delay, and 350% higher EE over the well-known benchmark caching schemes. Full article
(This article belongs to the Special Issue Radio Access Network Planning and Management)
Show Figures

Figure 1

Article
Recent Meta-Heuristic Algorithms with a Novel Premature Covergence Method for Determining the Parameters of PV Cells and Modules
Electronics 2021, 10(15), 1846; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151846 - 31 Jul 2021
Viewed by 313
Abstract
Currently, the incorporation of solar panels in many applications is a booming trend, which necessitates accurate simulations and analysis of their performance under different operating conditions for further decision making. In this paper, various optimization algorithms are addressed comprehensively through a comparative study [...] Read more.
Currently, the incorporation of solar panels in many applications is a booming trend, which necessitates accurate simulations and analysis of their performance under different operating conditions for further decision making. In this paper, various optimization algorithms are addressed comprehensively through a comparative study and further discussions for extracting the unknown parameters. Efficient use of the iterations within the optimization process may help meta-heuristic algorithms in accelerating convergence plus attaining better accuracy for the final outcome. In this paper, a method, namely, the premature convergence method (PCM), is proposed to boost the convergence of meta-heuristic algorithms with significant improvement in their accuracies. PCM is based on updating the current position around the best-so-far solution with two-step sizes: the first is based on the distance between two individuals selected randomly from the population to encourage the exploration capability, and the second is based on the distance between the current position and the best-so-far solution to promote exploitation. In addition, PCM uses a weight variable, known also as a controlling factor, as a trade-off between the two-step sizes. The proposed method is integrated with three well-known meta-heuristic algorithms to observe its efficacy for estimating efficiently and effectively the unknown parameters of the single diode model (SDM). In addition, an RTC France Si solar cell, and three PV modules, namely, Photowatt-PWP201, Ultra 85-P, and STM6-40/36, are investigated with the improved algorithms and selected standard approaches to compare their performances in estimating the unknown parameters for those different types of PV cells and modules. The experimental results point out the efficacy of the PCM in accelerating the convergence speed with improved final outcomes. Full article
(This article belongs to the Section Power Electronics)
Show Figures

Figure 1

Article
Fast Flux and Torque Control of a Double Inverter-Fed Wound Machine Considering All Coupling Interferences
Electronics 2021, 10(15), 1845; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151845 - 31 Jul 2021
Viewed by 373
Abstract
For efficient operation of the squirrel cage induction motor, the flux must be properly adjusted according to the torque. However, in such variable flux operation, the performance of torque control is limited by the flux control because it is not possible to measure [...] Read more.
For efficient operation of the squirrel cage induction motor, the flux must be properly adjusted according to the torque. However, in such variable flux operation, the performance of torque control is limited by the flux control because it is not possible to measure and control the rotor current that affects the flux. On the contrary, in a double inverter-fed wound machine (DIFWM), the inverter is connected to the rotor side, as well as the stator side, and the rotor current can be controlled. This controllability of the rotor currents improves the operation performance of a DIFWM. This article presents the decoupling current control method of a DIFWM for fast flux and torque control. Since the rotor flux is directly calculated by the stator and rotor currents, the bandwidth of the flux control can be improved to the bandwidth of the current controller, which means that the torque control also has the same bandwidth. In this article, a detailed current controller design method with a DIFWM feed-forwarding decoupling method to eliminate all coupling interferences is proposed. The simulation and experimental results regarding the DIFWM are presented to verify the torque and flux control performance of the proposed control method. Full article
Show Figures

Figure 1

Article
Characterization Techniques of Millimeter-Wave Orthomode Transducers (OMTs)
Electronics 2021, 10(15), 1844; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151844 - 31 Jul 2021
Viewed by 288
Abstract
We report on advanced techniques for the accurate characterization of millimeter-wave Orthomode Transducers (OMTs) enabling the derivation of the fundamental parameters of such devices, i.e., the insertion loss, the return loss, the cross-polarization, and the isolation. These techniques include standard frequency-domain and time-domain [...] Read more.
We report on advanced techniques for the accurate characterization of millimeter-wave Orthomode Transducers (OMTs) enabling the derivation of the fundamental parameters of such devices, i.e., the insertion loss, the return loss, the cross-polarization, and the isolation. These techniques include standard frequency-domain and time-domain VNA (Vector Network Analyzer) measurement methods, which can be applied to remove the effects of the waveguide transitions necessary to access the OMT ports and excite the desired modes. After reviewing the definition of the OMT parameters, we discuss the test equipment, the VNA calibration procedures as well as the VNA time-domain time-gating method for application in OMT characterization. We present simplified equations that relate the calibrated VNA measured quantities with the OMT S-parameters, illustrate various characterization methods, and examine various OMT experimental test setups. The advantages and disadvantages of each of the OMT characterization procedures are presented and compared among them. We provide a list of waveguide components required in the OMT test setups (adapters, loads, quarter-wave and longer waveguide sections, feed-horn, etc.), discuss the error terms introduced by such components and examine their impact on the measured values. Furthermore, we identify strategies to mitigate or remove the effects of the measured errors, to derive the desired OMT parameters. Different OMT configurations, with a distinct orientation of the waveguide input and outputs, are discussed. Although the presented techniques refer to the characterization of a specific configuration of a W-band OMT, the described methods can be applied to other OMT configurations and frequency ranges (from microwave to THz frequencies), therefore having a general validity. Full article
(This article belongs to the Section Microwave and Wireless Communications)
Show Figures

Figure 1

Article
Content Dependent Representation Selection Model for Systems Based on MPEG DASH
Electronics 2021, 10(15), 1843; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151843 - 31 Jul 2021
Viewed by 298
Abstract
A standard called MPEG Dynamic Adaptive Streaming over HTTP (MPEG DASH) ensures the interoperability between different streaming services and the highest possible video quality in changing network conditions. The solutions described in the available literature that focus on video segmentation are mostly proprietary, [...] Read more.
A standard called MPEG Dynamic Adaptive Streaming over HTTP (MPEG DASH) ensures the interoperability between different streaming services and the highest possible video quality in changing network conditions. The solutions described in the available literature that focus on video segmentation are mostly proprietary, use a high amount of computational power, lack the methodology, model notation, information needed for reproduction, or do not consider the spatial and temporal activity of video sequences. This paper presents a new model for selecting optimal parameters and number of representations for video encoding and segmentation, based on a measure of the spatial and temporal activity of the video content. The model was developed for the H.264 encoder, using Structural Similarity Index Measure (SSIM) objective metrics as well as Spatial Information (SI) and Temporal Information (TI) as measures of video spatial and temporal activity. The methodology that we used to develop the mathematical model is also presented in detail so that it can be applied to adapt the mathematical model to another type of an encoder or a set of encoding parameters. The efficiency of the segmentation made by the proposed model was tested using the Basic Adaptation algorithm (BAA) and Segment Aware Rate Adaptation (SARA) algorithm as well as two different network scenarios. In comparison to the segmentation available in the relevant literature, the segmentation based on the proposed model obtains better SSIM values in 92% of cases and subjective testing showed that it achieves better results in 83.3% of cases. Full article
(This article belongs to the Special Issue Immersive Quality of Experience Management and Evaluation)
Show Figures

Figure 1

Article
Serial RRAM Cell for Secure Bit Concealing
Electronics 2021, 10(15), 1842; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151842 - 31 Jul 2021
Viewed by 294
Abstract
Non-volatile memory cells are exposed to adversary attacks since any active countermeasure is useless when the device is powered off. In this context, this work proposes the association of two serial RRAM devices as a basic cell to store sensitive data, which could [...] Read more.
Non-volatile memory cells are exposed to adversary attacks since any active countermeasure is useless when the device is powered off. In this context, this work proposes the association of two serial RRAM devices as a basic cell to store sensitive data, which could solve this bothersome problem. This cell has three states: ‘1’, ‘0’, and masked. When the system is powered off or the data is not used, the cell is set to the masked state, where the cell still stores a ‘1’ or a ‘0’ but a malicious adversary is not capable of extracting the stored value using reverse engineering techniques. Before reading, the cell needs to be unmasked and it is masked afterwards until the next reading request. The operation of the cell also provides robustness against side-channel attacks. The presented experimental results confirm the validity of the proposal. Full article
(This article belongs to the Special Issue Resistive Memory Characterization, Simulation, and Compact Modeling)
Show Figures

Figure 1

Editorial
Special Issue on Computational Intelligence for Healthcare
Electronics 2021, 10(15), 1841; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151841 - 31 Jul 2021
Viewed by 292
Abstract
The number of patient health data has been estimated to have reached 2314 exabytes by 2020 [...] Full article
(This article belongs to the Special Issue Computational Intelligence in Healthcare)
Article
RESFIT: A Reputation and Security Monitoring Platform for IoT Applications
Electronics 2021, 10(15), 1840; https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10151840 - 31 Jul 2021
Viewed by 420
Abstract
The fast-paced adoption of smart devices has changed the Internet of Things (IoT) landscape, leading to the growth of smart environments and inclusion in many aspects of our society. In IoT applications, data collected from sensors and mobile devices are aggregated, processed, and [...] Read more.
The fast-paced adoption of smart devices has changed the Internet of Things (IoT) landscape, leading to the growth of smart environments and inclusion in many aspects of our society. In IoT applications, data collected from sensors and mobile devices are aggregated, processed, and analyzed to extract useful information and develop intelligent services. If the collected data is not trustworthy due to the damage or malicious input of some sensors, the quality of the service will be impacted. For reliable data collection and mining, it is mandatory to define robust security and trust models, suitable for the IoT application context. In this paper, we propose RESFIT, a platform that implements a reputation-based trust mechanism and an advanced application level firewall to cope with the above mentioned issues. Having a gateway-centric architecture, the proposed platform ensures minimal resource consumption at the node layer, and an integrated overview and control of the system state, through the cloud component and smartphone management application. Full article
(This article belongs to the Special Issue Security and Privacy for IoT and Multimedia Services)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop